The workers ended up injured while doing some welding at the terminal according to the Marcus McLellan of the Jefferson County Sheriff’s office. Officials from the company have not yet released any comments about the flash fire and the conditions of the employees.

“There is now no danger to the area around the plant”, the sheriff’s office said.

According to the company that owned the marine terminal, Sunoco Logistics, it appeared to involve a crude-oil pipeline connection.

The Nederland plant stores crude oil and other natural gases, with a storage capacity of approximately 24 million crude oil barrels, according to Sunoco’s website.

Friday night, L-Con contractors were working on a pipeline connection inside Sunoco Logistics, when a flash fire started.

“Usually vapor or there could be a liquid, it burns really rapid real fast,” said Deputy Marcus McLellan with the Jefferson County Sheriff’s Office. “There’s no more accelerant no more left to burn so it’s just real fast, real quick and usually extinguishes itself.”

That fire injured seven workers with four of them critically injured after suffering burns. Three workers have been released from the hospital, according to a company spokesperson.

“Working in refinery is a dangerous job,” said McLellan. “You have hazardous very volatile chemicals that your around every day. Whenever there is an incident it’s usually on the severe side.”